Overexposure to sunlight can cause premature aging of the skin and in some circumstances can lead to skin cancer. One method of preventing such skin damage is to avoid more than limited exposure to sunlight. An alternative preventive method involves the widespread use of commercially-available sunscreen compositions.
Sunscreen compositions come in a wide array of formulations including those which are preformulated to give a particular level of protection based upon an expected exposure to sunlight. The drawback with such formulations is that the user may become overexposed if the expected exposure level is underestimated.
Therefore, it is an object of this invention to provide a composition for protection from ultraviolet radiation, typically in the form of sunlight, comprising a photoresponsive element which adjusts the level of protection according to the exposure of radiation received by the user.
It is also an object of this invention to provide sunscreen compositions comprising organic molecules which undergo an efficient photoreaction, converting the molecule from a weakly-absorbing compound to a strongly-absorbing compound.
It is also an object to provide a method for obtaining protection from UV-A/B/C light through the use of compositions comprising derivatives of benzoins which undergo photolysis when exposed to UV-A/B/C light and yield benzofurans with large extinction coefficients in the UV-A/B/C region of the electromagnetic spectrum.